About This Gigapan

The Parfrey's Glen Formation is a Cambrian sandstone and conglomerate that lies directly on top of the 1.7 billion year old Baraboo Quartzite. The cobbles you see are all quartzite-- at the time this was deposited, ocean waves were lapping up against cliffs of Baraboo Quartzite. Large storm events would drag heavy cobbles (and even boulders) farther off-shore, which is what you see here.